fix: add build context to prod and staging services in docker-compose.yml

Without build: directive, docker compose tries to pull corescope:latest
from Docker Hub instead of building locally.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docker-compose.yml

@@ -5,6 +5,7 @@
 
 services:
   prod:
+    build: .
     image: corescope:latest
     container_name: corescope-prod
     restart: unless-stopped
@@ -26,6 +27,7 @@ services:
       retries: 3
 
   staging:
+    build: .
     image: corescope:latest
     container_name: corescope-staging
     restart: unless-stopped